Impact cushioning apparatus

ABSTRACT

An impact cushioning bumper comprises an elongated channelshaped contact member attached at its edges to an elongated mounting member having a face convex-out in cross-section toward the contact member. Within the channel are positioned upright slabs of elastomer which, when the contact member is moved toward the mounting member, are tensioned by stretching over its convex face.

United States Patent 1191 Walls et al. Oct. 22, 1974 IMPACT CUSHIONINGAPPARATUS 2,829,915 4/1958 75 Inventors: Harold D. Walls; Robert s.McGaughey, both Of White 3:614:148 97 Townshlp, Pa. 3 A M C I d l P d CFOREIGN PATENTS OR APPLICATIONS [7 Sslgnee I gusma l,()35.2l6 8/1953France 293/71 P n l,264,()76 /!961 Francc 293/71 P [22] Filed: July 2,1973 Primary ExaminerM. Henson Wood, Jr. [21] Appl 375542 AssistantExaminer-Robcrt Saifer Related US. Application Data Attorney, Agent,-orFirmBuell, Blenko & [63] Continuation-impart of Ser. No. 258,753, JuneI, Ziescnheim 1972, abandoned, Continuation-impart of Ser. No. 33l,328,Feb. 9, 1973, abandoned [521 US. Cl 293/88 293/72 293/87 impactCushioning bumper 99111199598 an elongated 6 channel-shaped contactmember attached at its edges 51 1111.01. Br 19/10 to an elongatedmounting member having a face 5 Field f Search 293/ 71 R, 71 p 72,vex-out in cross-section toward the contact member. 293/84 85 87 88267/1319 11 40219 Within the channel are positioned upright slabs ofelastomer which, when the contact member is moved 5 References Citedtoward the mounting member, are tensioned by UMTED STATES PATENTSstretching over its convex face. 2,089,500 8/1937 Ochadloski 293/71 P 21Claims, 7 ng gures 4 f, 5 ll ds 1o IMPACT CUSHIONING APPARATUS Thisapplication is a continuation-in-part of our applications Ser. No.258,753, filed June l, 1972, now abandoned, and Ser. No. 331,328, filedFeb. 9, 1973, now abandoned, both of which are incorporated by referenceherein and made a part hereof.

This invention relates to an impact cushioning apparatus for motorvehicles and the like. It is more particularly concerned with impactcushioning apparatus of that type which utilizes an elastomer for thecushioning agent.

Various types of impact cushioning or absorbing bumpers have beendevised using elastomers in compression for the cushioning material. Agreat disadvantage of bumpers of this type is the limited cushioningeffect obtainable in practical designs because of the narrow rangethrough which elastomers can be compressed before failing. For mostelastomers failure in compression occurs between about percent and 50percent deformation and even in the absence of failure the modulus ofelasticity increases so rapidly at high deformations that the energyabsorbing capacity becomes tively great deflection and so make possiblea softer stop. We have found, however, that an elongated bumperutilizing elastomer in tension as its sole or principal energy absorbingmedium and which provides a soft stop when it makes contact with a wallor other object which engages it along all or more of its contact facemay bottom and so provide a considerably harder stop when it makescontact with a pole or like object which engages only a limited portionof its contact face.

It is an object of our invention therefore to provide an impactcushioning bumper which will more uniformly cushion distributed andlocalized impacts. It is another object to provide such a bumper inwhich the principal cushioning agent is an elastomer in tension. It isstill another object to provide such a bumper which utilizes ascushioning agent elastomer in tension in combination with pneumaticmeans. Other objects of our invention will appear in the course of thedescription thereof which follows.

We have found that we can achieve the objects above mentioned byadjusting the relative dimensions and disposition of certain of theelements of our apparatus and, in certain embodiments, by providing thatapparatus with means for maintaining a gas under pressure therein. Ourbumper, in its preferred embodiment, comprises an elongatedchannel-shaped contact member adapted to'receive impact and be movedthereby, a mounting member toward which the contact member is moved, anddiscrete elements of elastomer spaced lengthwise of the bumper attachedat their ends to the contact member and which are stretched when thecontact member is moved toward the mounting member. When such a bumpermakes contact with an object over only a portion of the bumper lengththere will inevitably be localized distortion of the'contact member.

If this localized distortion of the contact member tends to reduce thecapacityof the elastomer elements to absorb energy by stretching,'theperformance of the bumper is impaired. Our bumper to be describedhereinafter is designed to minimize this undesirable effect of localizeddistortion. Embodiments of our invention pres ently preferred by us areillustrated in the attached figures', to which reference is now made.

FIG. I is a perspective, broken away in part, of an article of ourinvention;

FIG. 2 is a cross-section through the article of FIG. 1 on the plane 22;f

FIG. 3 is a cross-section through the article of FIG. 1 on the sameplane as that of FIG. 2 but showing the deformation of the article upondistributed impact with a plane surfaace;

FIG. 4 is a plan, broken away in part, of the article of FIG. 1 butshowing the deformation of the article upon localized impact;

FIG. 5 is a perspective of a type of insert used in our invention;

FIG. 6 is a perspective of elements of another embodiment of ourinvention; and 7 FIG. 7 is a cross-section of that embodiment.

Our article comprises an elongated channel-shaped contact member 1affixed toan elongated mounting member 5. The web 4 of member 1 isgenerally convex.- out and the upper and lower flanges 2 and 3,respectively, diverge from web 4 toward mounting member 5. Web 4 isformed with a centrally located longitudinal corrugation 10 which isconcave-out. The edges 14 and 15 of flanges 2 and3, respectively,terminate in beads 8 and 9 which are sealed to mounting member 5 byfacing member 6 which is elongated likemember 5 and is provided withagroove along each edge into which beads 8 and 9 fit. Facing member 6 isattached to mounting member 5 by bolts 17 which pass through holes inmember 5 and are tapped into threaded holes in member 6. The surface 7of facing member 6 oriented toward contact member 1 is convex-out.

Within contact member 1, which is closed at its ends, are positioned aplurality of upright slabs or panels 11 of elastomer spaced fromeachother and disposed crosswise of contact member .1. These slabs 11 areattached at the tops and bottoms to flanges 2 and 3, respectively, andat an end to web 4. The other end 12 of the slab stops just short ofsurface 7 of facing member 6. This end 12 isgenerally plane. The spacebetween successive slabs ll is filled by blocks of foamed elastomer 16.The portion 14 of flange 2 between end 12 of slab 11 and bead 8 has athickness less than that of the remainder of flange 2 and thecorresponding portion 15 of flange 3 likewise has a thickness less thanthat of the remainder of flange 3. A valve 13 is positioned in flange 2throughwhich air or other gas may be introduced to increase the pressurewithin our article above atmospheric pressure. It is convenient to moldcontact member l with its thinner extremities l4 and 15, beaded edges 8and 9, and enclosed slabs or panels 11 in one piece from an elastomersuch as polyurethane.

The operation of our article will be explained in connection with theforegoing description thereof as well as the attached figures. Whencontact member 1 meets an unyielding object such as a wall, it tends todeform in the manner shown in FIG. 3. The convex web 4 flattens out,flanges 2 and 3 are forced back toward facing member 6 and their outeredges spread apart, stretching slabs 11 over the convex face 7 of facingmember 6. The bulk of the energy of the impact is absorbed by thestretching of the slabs 11 positioned within contact member 1. We havefound that when a bumper makes contact with an object over only aportion of the bumper length, as is illustrated in FIG. 4, there is atendency for the entire bumper to deflect up or down in the area ofcontact. This probably happens because the bumper rarely meets theobject squarely. If the contact member 1 deflects either way, one or theother of its flanges 2 and 3 is tensioned to some extent but the slabs11 buckle, and the energy absorbing capacity of the bumper isconsiderably impaired. We have also found that we can minimize thisundesirable tendency by constructing contact member 1 so that flanges 2and 3 diverge, as shown in FIG. 2. The distance between them at theirouter edges is greater than that at web 4.

A contact member so constructed is much more diffi-- cult to deflectupwardly or downwardly than one having parallel flanges. The stabilityof the member is sufficient for our purposes if the divergence of theflanges is about one in six, that is to say about one unit measuredvertically for each six units measured horizontally from front to backof the bumper.

The energy absorption characteristics of our bumper are also improved ifedge portions 14 and 15 are more flexible than flanges 2 and 3. This ismost easily achieved by thinningedge portions 14 and 15 of flanges 2 and3 as has been mentioned. Those flanges buckle when contact member 1 isforced back toward facing member 6 by an impact. In our bumper thisbuckling is largely accommodated by outward bulging or folding of edgeportions 14 and 15, as is shown in FIG. 3, which allows the remainder ofcontact member 1 to move back with less compression than would occur ifthe buckling were more uniformly distributed. When contact member 1receives localized impact, as from a pole or the like, a contact memberconstructed in this way absorbs more energy before bottoming than does asimilar bumper with no edge thinning. We find that edge portions 14 and15 about l percent to 20 percent thinner than flanges 2 and 3 providethe benefits above mentioned. v V

Corrugation 10 in web 4 strengthens that web against bending underlocalized impact and likewise stiffens the slabs or panels 11 and soretards their buckling under those conditions. It is buckling of thoseslabs, as is'illustrated in FIG. 4, which impairs the energy absorptionof the bumper under localized impact and we have found that thisbuckling is further retarded if the interior of our bumper is filledwith a gas, such as air,

at a pressure somewhat above atmospheric pressure.v

For this purpose, valve13 is provided and through it we introducedcompressed air or other gas. This compressed air fills the interior ofour bumper by flowing freely through the open spaces between the ends 12of slabs 11 and the convex surface 7 of facing member 6. We believe thatwhen contact member 1 is forced back towards facing member 6 by animpact it further compresses the, air in the bumper, and in regions awayfrom the region of localized impact that compressed air tends to expandcontact member 1, thus dissipating the energy of impact by stretchingslabs 11 in those regions. We find that a guage pressure on the order ofhalf an atmosphere is sufficient in our article.

The blocks of foamed elastomer 16 which fill the spaces betweensuccessive slabs 11 support those slabs against lateral buckling. Thisaction is enhanced by making the blocks 16 of dimensions somewhatgreater than those of the spaces to be filled and compressing the blockswhen they are inserted. The tendency of the foamed elastomer to expandmaintains slabs 11 under tension. For this purpose, we prefer todimension the blocks 16 with the samewidth and depth as the spacesbetween slabs 11 but with a height greater than the distance betweenflanges 2 and 3. We prefer to make blocks 16 out of foamed polyurethane.

Our invention also comprehends other support meansfor the elastomerslabs. FIG. 5 illustrates an insert I9 conveniently made of a moldedelastomer which is inserted in the spaces between the slabs 11. Theinsert has parallel end walls 20 which have the contour of across-section of shell 1 such as is shown in FIG. 2, flat top and bottomwalls 21 and a curved front wall 22. The back wall 23 which facesmounting member 5 is planar. and generally rectangular in shape. Theinsert is provided with a hollow center 24 which opens out of back wall23, the thickness of the walls so formedv being proportioned to providethe desired amount of support. The slabs 11 may also be supported bysealed cells of a shape similar to that of insert 19 except for theabsence of a cavity 24. Those cells are conveniently made of relativelythin elastomer sheet and are sealed so as to formcushions with theircontained air or other gas. The cushioning effect of the gas filledcells is-enhanced by disposing within them a foamed elastomer of thetype previously mentioned.

A further modification of our invention is illustrated in FIGS. 6 and 7.We have found that it is desirable for some purposes to make the contactmember of our bumper of modular units. In this way, bumpers for vehiclesof different widthssuch as trucks, buses and pass'enger cars can be madeby assembling the appropriate number of identical contact member moduleson a mounting member. Twosuch modules 26 are shown side-by-side in FIG.6. As before, the contact member module has a convex-out web 4 providedwith a central concave-out corrugation 10, an upper flange 2, and alower flange 3, which diverge fromweb 4. Module 26 is closed at each endby a flat wall 27 so that adjacent modules fit closely together.

FIG. 6 also illustrated a modified form of the elastomer slab structure.Vertical slabs or panels 28 spaced from each other are attached alongtheir upper sides to flange 2, along their lower sides to flange 3, andalong their front ends to web 4. A horizontal slab 29 is attached ateach end to wall 27 of the module and is attached to vertical slabs28-28 where it intersects them. FIG. 7 shows a module 26 attached tomounting member 5. The beads 8 and 9 of top and bottom flanges 2 and 3are clamped between a tray 30 and a facing member 31. Tray 30 .has arectangular flat bottom 32 surrounded by an upstanding rim 33dimensioned to receive module 26. Facing member 31 comprises arectangular plate 34 sized to fit within tray 30 with clearance allaround for the flanges and ends of module 26. All four edges of plate 34are bent over, as at 37, so as to clear the bead, 8 for example, of the.module flange and clamp it between turned-over edge 37 and the rim 33 oftray 30. The other face of plate 34 is provided with an upstanding rib35 positioned longitudinally of plate 34 and terminating in a widermember 36 which has a convex-out face toward contact member module 26.Facing member 31 and tray 30 are fastened to mounting member 5 by bolts17.

The embodiments of our invention illustrated in FIGS. 6 and 7 operate inthe same way as those previously described herein. When web 4 of contactmember 26 meets an obstacle it is forced back towards member 36. Flanges2 and 3 tend to move outwardly from each other and elastomer slabs 28-28as a result are stretched over the convex surface of member 36.Horizontally positioned slab 29 braces vertical slabs 2828 so as toresist their buckling. Buckling forces transmitted to an end wall 27 ofmodule 26 are resisted by adjoining module 26, where modular units areused. The arrangement of slabs 28 and 29 shown in FIG. 6 for a modularcontact unit 26 is also suitable for a unitary contact member extendingthe length of the bumper. In both cases, that structure providesimproved resistance to localized impact as well as to distributedimpact, with less danger of bottoming.

Our module 26 is illustrated as having a dimension greater along thebumper than crosswise of it. Preferably, its dimension crosswise of thebumper would be that appropriatevfor a passenger vehicle. We use thesame module for the wider bumpers required for busses, for example, bymaking the module length equal to the width of a bus bumper and mountingthe modules on mounting member 5 with the longer dimension crosswise ofthe bumper.

Although we have described and illustrated embodiments of our inventionin which the energy absorbing elastomer is attached to the impactreceiving member, the movement of which stretches the elastomer over themountingmember, our invention also encompasses the complementarystructure in which the elastomer is attached to the mounting member andis stretched over the moving contact member. The mounting member in theembodiments of our invention need not necessarily be a member separatefrom the vehicle but may be a structural element of the vehicle itself.

In the foregoing description the words top,, bottom," upper, lower,vertical,. vertically, horizontal," horizontally, and upright are usedin the context of a conventional bumper positioned crosswise of avehicle and parallel to the ground.

In the foregoing specification we have described a presently preferredembodiment of this invention, however it will be understood that thisinvention can be otherwise embodied within the scope of the followingclaims.

We claim:

1. Impact cushioning apparatus comprising a mounting member adapted tobe attached to the article to be cushioned, a contact member adapted toreceive impact and be moved toward the mounting member thereby, one ofthose members being U-shaped in vertical cross section with the open endof the U facing the other member, and elastomeric means interposed be--tween the contact memberand the mounting member ing, those meanscomprising a plurality of slabs of elastomer spaced from each other andpositioned in planes parallel to saidvertical cross section oftheU-shaped member.

2. Apparatus of claim 1 in which the elastomeric means are affixed tothe contact member.

3. Apparatus of claim '1 in which the other member is convex in verticalcross section facing the open end of the U.

4. Apparatus of claim 3 in which the face of the mounting member is theconvex face.

5. Apparatus of claim 1 in which the members are attached to each otheralong the edges defined by the open ends of the U-shaped cross section.

6. Apparatus of claim 5 in which the contact member is readilydeformable outwardly in planes parallel to its cross-section so that theelastomeric means are stretched by that deformation.

7. Apparatus of claim 5 in which the contact member is channel-shapedhaving a web with a convex-out impact surface and flanges diverging fromthe web flat between the web and the edges.

8. Apparatus of claim 7 in which the slabs of elastomer are affixed tothe channel-shaped contact member, the flanges of the channel-shapedcontact member extend beyond the free edges of the slabs, and theextended portionof the flanges are more flexible than the remainingportion.

9. Apparatus of claim 8 in which the extended portions of the flangesare-thinner than their remaining portions.

10. Apparatus of claim 5 in which the flanges of the channel-shapedcontact member are sealed to the mounting member, and including a valveadapted to admit gas under pressure to the interior of the contactmember..

11. Apparatus of claim 10 in which the interior of the apparatus isfilled with gas at a pressure above atmospheric pressure.

12. Apparatus of claim 11 in which the pressure of the gas is about halfan atmosphere.

13. Apparatus of claim 1 in which the free ends of the slabs are spacedfrom the other member a distance sufficient to provide free flow of gasinto and out of a space between'slabs.

14. Apparatus of claim 13 in which the spaces between the plurality ofslabs ofela'stomer contain yieldable means for holding those slabsupright.

15. Apparatus of claim 14 in which the yieldable means comprise a foamedcompressible material.

16. Apparatus of claim 14 in which the yieldable means comprise a moldedelastomer.

17. Apparatus of claim 16 in which the molded elastomer comprises atleast one slab of elastomer positioned normal to the other slabs.

l8. -Apparatus" 'of claim 14 in which the yieldable means comprise agas-filled cell.

19. Apparatus of claim 1 elongated in the direction of the contactsurface of the article to be cushioned in which the contact membercomprises a plurality of modules positioned adjacent each other alongthe mounting member, each module having an impactreceiving surface andenclosing a plurality of the slabs of the elastomer and a portion of theother member.

20. Apparatus of claim 19 in which the module is made of an elastomer,is open toward the mounting member with walls adjacent the mountingmember formed with a turned-in bead, and including a plate inserted intothe module covering the head on all sides,

the plate on itsside away from the mounting member other member isprovided with a surface convex-out carrying the portion of the othermember, and means only in planes normal to the direction of elongationoffastening the plate to the mounting member. the apparatus. 7 v 21.Apparatus of claim 19 in which the portion of the

1. Impact cushioning apparatus comprising a mounting member adapted to be attached to the article to be cushioned, a contact member adapted to receive impact and be moved toward the mounting member thereby, one of those members being U-shaped in vertical cross section with the open end of the U facing the other member, and elastomeric means interposed between the contact member and the mounting member and affixed to the U-shaped member so that those means are stretched over the other member by that movement of the contact member towards the mounting member and retard that movement by that stretching, those means comprising a plurality of slabs of elastomer spaced from each other and positioned in planes parallel to said vertical cross section of the U-shaped member.
 2. Apparatus of claim 1 in which the elastomeric means are affixed to the contact member.
 3. Apparatus of claim 1 in which the other member is convex in vertical cross section facing the open end of the U.
 4. Apparatus of claim 3 in which the face of the mounting member is the convex face.
 5. Apparatus of claim 1 in which the members are attached to each other along the edges defined by the open ends of the U-shaped cross section.
 6. Apparatus of claim 5 in which the contact member is readily deformable outwardly in planes parallel to its cross-section so that the elastomeric means are stretched by that deformation.
 7. Apparatus of claim 5 in which the contact member is channel-shaped having a web with a convex-out impact surface and flanges diverging from the web flat between the web and the edges.
 8. Apparatus of claim 7 in which the slabs of elastomer are affixed to the channel-shaped contact member, the flanges of the channel-shaped contact member extend beyond the free edges of the slabs, and the extended portion of the flanges are more flexible than the remaining portion.
 9. Apparatus of claim 8 in which the extended portions of the flanges are thinner than their remaining portions.
 10. Apparatus of claim 5 in which the flanges of the channel-shaped contact member are sealed to the mounting member, and including a valve adapted to admit gas under pressure to the interior of the contact member.
 11. Apparatus of claim 10 in which the interior of the apparatus is filled with gas at a pressure above atmospheric pressure.
 12. Apparatus of claim 11 in which the pressure of the gas is about halF an atmosphere.
 13. Apparatus of claim 1 in which the free ends of the slabs are spaced from the other member a distance sufficient to provide free flow of gas into and out of a space between slabs.
 14. Apparatus of claim 13 in which the spaces between the plurality of slabs of elastomer contain yieldable means for holding those slabs upright.
 15. Apparatus of claim 14 in which the yieldable means comprise a foamed compressible material.
 16. Apparatus of claim 14 in which the yieldable means comprise a molded elastomer.
 17. Apparatus of claim 16 in which the molded elastomer comprises at least one slab of elastomer positioned normal to the other slabs.
 18. Apparatus of claim 14 in which the yieldable means comprise a gas-filled cell.
 19. Apparatus of claim 1 elongated in the direction of the contact surface of the article to be cushioned in which the contact member comprises a plurality of modules positioned adjacent each other along the mounting member, each module having an impact-receiving surface and enclosing a plurality of the slabs of the elastomer and a portion of the other member.
 20. Apparatus of claim 19 in which the module is made of an elastomer, is open toward the mounting member with walls adjacent the mounting member formed with a turned-in bead, and including a plate inserted into the module covering the bead on all sides, the plate on its side away from the mounting member carrying the portion of the other member, and means fastening the plate to the mounting member.
 21. Apparatus of claim 19 in which the portion of the other member is provided with a surface convex-out only in planes normal to the direction of elongation of the apparatus. 